Method and apparatus for separating magnetic material from a slurry

Abstract

A method and apparatus for separating magnetic material from a slurry is disclosed, the method including the steps of providing a first moving surface, depositing the slurry onto the first moving surface, attracting at least a portion of the magnetic material of the slurry onto the first moving surface by first magnetic means, arranging the first moving surface such that liquid from the slurry is removed due to the portion of the magnetic material being attracted to the moving surface by the first magnetic means to form a magnetic material cake, separating an inner portion of the magnetic material cake from an outer portion of the magnetic material cake, with respect to the first moving surface, such that the inner portion has a lower liquid content than the outer portion.

The invention claimed is: 
     
       1. A method of separating magnetic material from a slurry, the method comprising the steps of:
 providing a first moving surface; 
 depositing the slurry onto the first moving surface; 
 attracting at least a portion of the magnetic material of the slurry onto the first moving surface by first magnetic means; 
 arranging the first moving surface such that liquid from the slurry is removed due to the portion of the magnetic material being attracted to the moving surface by the first magnetic means to form a magnetic material cake; and 
 separating an inner portion of the magnetic material cake from an outer portion of the magnetic material cake, with respect to the first moving surface, such that the inner portion has a lower liquid content than the outer portion. 
 
     
     
       2. A method according to  claim 1 , wherein the step of separating comprises the sub-steps of:
 providing at least one of a blade or a knife means; and 
 arranging the blade or knife means to separate the inner portion from the outer portion of the magnetic material cake. 
 
     
     
       3. An apparatus according to  claim 2 , wherein the knife or blade means comprises at least one of a hollow channel or a hollow portion for directing a jet of air. 
     
     
       4. A method according to  claim 3 , wherein at least one of the blade means, the knife means, or the jet of air is adjustable for varying the liquid content of the inner portion. 
     
     
       5. A method according to  claim 1 , wherein the step of separating comprises directing a jet of air to separate the inner portion from the outer portion of the magnetic material cake. 
     
     
       6. A method according to  claim 1 , wherein the inner portion of the magnetic material cake has a liquid content in a range of 5-8%. 
     
     
       7. A method according to  claim 1 , wherein the outer portion of the magnetic material cake is returned to the first moving surface for further processing. 
     
     
       8. A method according to  claim 1 , further comprising at least one spray nozzle for directing liquid onto the first moving surface to remove silica from the magnetic material cake. 
     
     
       9. A method according to  claim 1 , further comprising the steps of:
 depositing the liquid from the slurry onto a second moving surface; 
 attracting at least a portion of residual magnetic material of the liquid onto the second moving surface by a second magnetic means; and 
 arranging the second moving surface such that the liquid is removed due to at least a portion of the residual magnetic material being attracted to the second moving surface by the second magnetic means. 
 
     
     
       10. A method according to  claim 9 , wherein the residual magnetic material is returned to the first moving surface for further processing. 
     
     
       11. A method according to  claim 9 , wherein at least one of the first or the second moving surfaces is a surface of a rotating drum. 
     
     
       12. A method according to  claim 9 , wherein at least one of the first or the second moving surfaces is a surface of at least one belt. 
     
     
       13. A method according to  claim 9 , wherein at least one of the first or the second magnetic means is a permanent magnet including rare earth magnets. 
     
     
       14. An apparatus for separating magnetic material from a slurry, the apparatus comprising:
 a first moving surface comprising first magnetic means; 
 the first moving surface arranged such that liquid from the slurry is removed due to the portion of the magnetic material being attracted to the first moving surface by the first magnetic means to form a magnetic material cake; and 
 separation means arranged such that an inner portion of the magnetic material cake is separated from an outer portion of the magnetic material cake, with respect to the first moving surface, wherein the inner portion has a lower liquid content than the outer portion. 
 
     
     
       15. An apparatus according to  claim 14 , wherein the separation means comprises at least one of a blade means or a knife means for separating the inner portion from the outer portion of the magnetic material cake. 
     
     
       16. An apparatus according to  claim 15 , wherein the knife or blade means comprises at least one of a hollow channel or a hollow portion for directing a jet of air. 
     
     
       17. An apparatus according to  claim 16 , wherein at least one of the blade means, the knife means, or the jet of air is adjustable for varying the liquid content of the inner portion. 
     
     
       18. An apparatus according to  claim 14 , wherein the separation means comprises a jet of air for separating the inner portion from the outer portion of the magnetic material cake. 
     
     
       19. An apparatus according to  claim 14 , wherein the inner portion of the magnetic material cake has a liquid content in a range of 5-8%. 
     
     
       20. An apparatus according to  claim 14 , wherein the outer portion of the magnetic material cake is returned to the first moving surface for further separation. 
     
     
       21. An apparatus according to  claim 14 , further comprising at least one spray nozzle for directing liquid onto the first moving surface to remove silica from the magnetic material cake. 
     
     
       22. An apparatus according to  claim 14 , further comprising:
 a second moving surface with second magnetic means, 
 wherein:
 the second moving surface is configured to receive the liquid from the slurry and to attract at least a portion of residual magnetic material from the liquid onto the second moving surface by the second magnetic means; and 
 the second moving surface is further configured such that the liquid is removed due to at least a portion of the residual magnetic material being attracted to the second moving surface by the second magnetic means. 
 
 
     
     
       23. An apparatus according to  claim 22 , wherein the residual magnetic material is returned to the first moving surface for further processing. 
     
     
       24. An apparatus according to  claim 22 , wherein at least one of the first or the second moving surfaces is a surface of a rotating drum. 
     
     
       25. An apparatus according to  claim 22 , wherein at least one of the first or the second moving surfaces is a surface of at least one belt. 
     
     
       26. An apparatus according to  claim 22 , wherein at least one of the first or the second magnetic means is a permanent magnet including rare earth magnets.